Important Information about Techniques

See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.

Description

The objective of this technique is to use Unicode right-to-left marks and left-to-right
marks to override the HTML bidirectional algorithm when it produces undesirable results.
This may be necessary, for instance, when placing neutral characters such as spaces or
punctuation between different directional text runs. The concepts used in this technique
are described in What you need to
know about the bidi algorithm and inline markup.

Unicode right-to-left marks and left-to-right marks can be entered directly or by
means of character entities or numeric character references, as shown here.

left-to-right mark: &lrm; or &#x200e; (U+200E)

right-to-left mark: &rlm; or &#x200f; (U+200F)

Due to the bidi algorithm, a source code editor
may not display character entities or numeric
character references as expected.

Examples

Example 1

This example shows an Arabic phrase in the middle of an English sentence. The exclamation point is part of the Arabic phrase and should appear on its left. Because it is between an Arabic and Latin character and the overall paragraph direction is LTR, the bidirectional algorithm positions the exclamation mark to the right of the Arabic phrase.

The title is "مفتاح معايير الويب!" in Arabic.

Visually-ordered ASCII version (RTL text in uppercase, LTR in lower):

the title is "HCTIWS SDRADNATS BEW!" in arabic.

Inserting a Unicode right-to-left mark in the code immediately after the exclamation mark positions it correctly when you view the displayed text (see below). You can use a character escape or the (invisible) control character to insert the right-to-left mark.

Related Techniques

Tests

Procedure

When text changes direction, check whether neutral characters such as spaces or
punctuation occur adjacent to text that is rendered in the non-default
direction.

When #2 is true and the HTML bidirectional algorithm would produce the wrong
placement of the neutral characters, check whether the neutral characters are
followed by Unicode right-to-left or left-to-right marks that cause neutral
characters to be placed as part of the preceding characters.

Expected Results

Check #3 is true.

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.